Clamping device for extension leveling rods



Jan. 26, 1932. A. LANGSNER CLAHPING DEVICE FOR EXTENSION LEVELING RODS Filed Aug. 29. 1927 r w 8 5 arias: WW 4 6 1 w h QAMKMWEEQ 1w a Patented Jan. 26, 1932 UNITED SlAl'ES P ADOLPI'I LANGSNER, OF CHICAGO, ILLINGIS, ASSIGNGR '10 EUGENE IlIE-TZG-EN COMPANY,

013 CHICAGO, ILLINOIS,A CQRPGRATION OF DELAWARE CLAMPING DEVICE FUR EXTENSION" LEVELING RODS Application filed August 29, 1927. Serial No. $316,303.

My invention relates to leveling rods used by surveyors and others, and especially to an extension leveling rod composed of two sections, whereby the rods may be extended in length and may be held and locked in such position of adjustment. Rods of this type are provided with a lower section designed to rest upon the ground and are provided with scale markings on the front thereof.

section to slide thereon and this upper section rarrics the target vertically adjustable thereon. l-leretoforc these extension leveling rods have been provided with clamps, generally adjustable, for holding the upper slidable section in its extreme extended position oi adjustment with respect to the lower section so that the target might be raised sulileiently high to take measurements at unusual heights. An improved type of such a clanming means is shown in my eopending application Serial No. 174,278, filed March 10, 1927.

Experience has shown, however, that the clamping device shown in my prior application and other existing clamping devices have been ineilective positively to hold the upper sectir'in in its extreme extended position with respect to the lower section, and considerable annoyuince and loss of time and much error in measurements has been occasioned by the necessity of re-adjusting the upper slidable section, with respect to the lower section, due to the fact that when the operator of the M leveling rod has taken a measurement in one position andthen moves the rod to a new location, to take a subsequent measuren'ient, in the very act of placing the leveling rod on the ground, be generally drops the lower section into contact with the ground. The impact caused by the dropping off this section on the ground causes the upper section to shift slightly downwardly even in spite of the clamping cevice which is supposed to hold it firmly in extreme extended position, so that the accurate setting of the upper section is disturbed and the two sections must be reset before taking the next measurement.

One of the ob ects of my present inventlon,

is to provide a clamping device for a leveling rod, which is constructed and arranged positively to lock the two sections in such extreme extended position so that these impacts of the lower section on the ground cannot dis turb the adj ustmentof the upper section, and the present clampingdevice is arrangednot only for accomplishing this positive interlock, but it is also. constructed and arranged to provide means for firmly clamping the two sections together when thus positively locked.

A further object of my invention resides in providing a leveling rod with anadjustable clamping means, shown in my before mentioned application, which is adapted to adjustably press the two sections together to hold them in extended position, and providing as an additional clamping means, the combined positive lock and adjustable clamp hereinbefore described, the two clamping devices being situated adjacent one another, but slightly spaced apartvvhen thetwo sections are in extended position, wl'iercby the upper section will be not only securely locked, but the two sections will be firmly clamped together at the two points along their over-lapping lengths. In addition this arrangement combines with the disposition of a clip positioned on the lower end of the upper section and surrounding the up per portion of the lower section whereby my improved combined lock and clamp is located intermediate to the clip and the claniping means of my first application, so that with this last mentioned construction there is a relation of three holding means in series along the over-lapped portions of the upper and lower sections. l

Another object of my invention is to con struct my improved clamping device so that in one position of adjustment it is freely operative automatically to lock the upper and lower sections together when they are moved relatively to their finally extended position, and in another shift position, firmly to clamp the two sections together.

A further object of my inventiton resides in providing a modified form wherein the plunger constituting one of-the locking members is normally spring pressed outwardly so that its nose will not scrape against or otherti l wise mar the divisional marks on the other section. In this construction the plunger is threaded so as to engage the threaded nut on the other section whereby when the two sections are extended to extreme position of adjustment, which is definitely determined by positive stops located on the two sections, the plunger may be pressed inwardly so that the threads are engaged and the two sections may thus be clamped firmly in this fully extended position.

These and other objects of my invention will be apparent from a perusal of the following specification when taken in connection with the accompanying drawings, wherein,

Figure 1 is a perspective view of a modified form showing the two sections in fully extended position.

. Figure 2 is a similar-view showing the sections in closed position.

Figure 3 is a perspective view showing the turning head of the plunger, and

Figure 4 is a sectional View taken through Figure 3. r V

Referring now to the drawings, the rod is formed in two sections, a lower and an upper sectio 12 in a mannercommon to extension leveling rods. These sections are suitably formed so that the usual target not shown may be slid lengthwise either along the upper section or along the lower section. The upper section may be designated as the movable section. The lower section is de signed to rest upon the ground or any other support.

As shown in the drawings, the two sections are adapted to be held in slidable assembled relation by means of the clip 13 preferably fastened to one face of the bottom portion of the upper section 12. This clip is of the usual U-shaped formation and is provided with the usual aperture through which the indicating marks on the front face of the lower section may be viewed. In addition,

' the lower end of the'sectio-n 10 is provided with the usual stop or abutment 14 against which the bottom end of section. 12 rests, when the upper and lower sections are slid into compact position as shown in Figure 2.

In the practical operation of such an extension, leveling red when it is desired to take measurements of increased height, the movable section 12 is slid upwardly to extreme position of adjustment and the target may then beslid vertically to desired adjust M tionsof the two sections in firm and in parallel relation, whereby accurate measurements are assured.

My present construction comprehends an arrangement which permits the clamping means automatically to come into operation as the sectionsare slid relatively and at a tion 12 with a bore or recess 16 entirely therethreugh. In addition I provide asection 12 with a hand operated plunger adapted to be mounted in, and to project through the opposite ends of this bore 12. This plunger has a preferably enlarged portion 18 formed with a turning head 20 and a reduced portion 22 at the outer end thereof, separated from the enlarged head 18 by means of the thread 24. In addition this plunger is formed-with a cross-pin adapted to confine a spring 28 between it and a plate 30'closing the outer end of tllQ'IQCQSS- 16. This plate is preferably attached to the section by means of The plate is formed with a bore to permit the plunger to pass freely therethrough. The section 10 is provided with a recess in which is seated a nut 32 internally threaded to receive the thread 24 on the plunger. This nut 32 is provided with lateral wings whereby it may be fastened int-he sectionlO. v

As by reference to Figure 4 of the drawings, it will be not-iced that the reduced end 22 of the plunger is su-fiiciently small to project freely into the hollow portion of the nut 32 without contacting therewith and I'preferably bevel the lower portion of the opening in the nut so thatthe plunger .will pass readily thereinto when the upper section is moved upward with respect to the lower sec- T 'tion. This bevel portion of the nut. permits the reduced end 22 of the plunger to be pushed into and threadingly engage in the hollow nut whereby it locks-the two sections,

when the upper section reaches its'extreme extended position as indicated in Figure 1.

The plunger 18 is provided with a spring 28 which encircles theplunger and rests at one end against a shoulder 29 formed at the bottom of the recess 16 and bears at its upper 4 end against a diametrical pin 26 carried by the plunger and having ends extending outwardly thereof into the recess 16 so that the spring normally urges the plunger away from the nut 82. v I

i It will be noticed that the recess 16 is of suflicient depth to permit the plunger to'be ur ed longitudinally outwardly or .to the right, as seen in Figure 4, by the spring so that when the threads 24; become disengaged be automatically disengaged from the hollow nut 32, and the locking devices will then be disengaged so that the sections can be freely slid relatively to each other. \Vhen the upper and lower sections have reached their extreme point of extension, the two overlapped portions of these sections, as shown in Figure 1, may be firmly clamped together in such position by pushing the plunger head or knob 20 until the threaded portion 24 of the plunger comes into threaded engagement with the threads of the nut 32 and by then rotating the knob 20. This threaded engagement serves to draw the contacting faces of the two sections closely togcther and thus provides a firm flat engagement of these two overlapped portions of the sections throughout their entire length It will be a lso observed that this clamping action is intermediate between the clip 13 and clamping device 33 which latter device, as hereinbcitore stated, is constructed in accordance with my hereinbeforc recited application and which clamp in general comprehends a turning wheel 3d adapted to adjust a threaded screw so that the end of the screw presses inwardlv against the section 12 whereby to hold the two sections in .[irm clamping engagement. In this instance the clamp 33 is, of course, carried by the upper end of the section 110 as set forth in such prior application. lly means of this arrangement a locking and clamping pressure of my present invention comes at a point which is intermediate to clip 13 and the upper clamp 33 thereby providing an extended binding at three points and sub stantially coextensive with the length of the overlapped portions of the two sections.

Thus I have provided a simple and economical type of combined positive locking and clamping device for either holding the two sections in clamped position or for locking them positively in extended position, or the same lock will accomplish both locking and clamping functions when the two sections are in extreme extended posit-ion. It will be appreciated that my first clamping device herein shown may replace the clamping device hcreinhcfore described and claimed in my prior application and that I do not need both clamping devices as shown in Figure 1 of the drawings except that the use or both of them provides a more extended clampin pressure along the length of the overla mcd portions when the two sections are in extreme extended position.

In this construction the clip 13 on the lower part of the section is adapted to abut a stop ll l carried on the upper part of the section 1-0 and this stop 14 is located so that it will abut the upper edge of the clip 13 when the two sections come to their position of extreme extended adjustment. When this position is reached the plunger 18 on thesection 12 will also come opposite and into registration with the hollow threadednut 32 so that the plunger 18 may then be pressed inwardly so that its threads 24 can engage the threads of the nut whereby the plunger may be screwed inward- 1y firmly to lock and clamp the two sections in such position of extended adjustment.

It is thought that the invention and numerous of its attendantadvantages willbe understood from the foregoing description and it is obvious thatnumerous changes maybe made in the form, construction, and arrangement of the several parts without departing from the spirit or scope of my invention or sacrificing any ot'its attendant advantages; the form herein described being a preferred embodiment for the purpose of illustrating my invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: i

1. In a device of the class described, a first section and a second section slidable relatively thereto, one of said sections having a recessed socket thereon formed with a threaded bore, the other section having a bore and having a plunger with its ends passing through said bore, one end of said plunger having a turning member thereon and the opposite end of the plunger having a reduced end of smaller diameter than the bore of said socket, said plunger having a portion adjaw cent said reduced end provided with a thread adapted to screw into the thread of the bore ofthe socket, and spring means for normally projecting said plunger so asto disengage the reduced end from the socket,

2. In a device of the class described, the combination of two sections relatively slidable, a plunger carried by one of said sections, said plunger having a portion adapted to project within a recess in the other section to lock said sections from sliding movement, means normally, urging the plunger portion away from the recess, said plunger having a portion adapted in response to the rotation thereof positively to engage the other section to draw said sections into clamping engagement when so locked. 1 a

3. In a device of the class described, the combination of two sections assembled for relative sliding movement to a position of BX: treme'extension, a locking member comprising a slidable plunger carried by onesection and adapted to engage the'other section in response to the longitudinal movement of the plunger to hold said sections positively locked from sliding movement, ineansnormally urging the plunger portion away from the recess, said plunger being capable of rotatable movementand having means to positively engage the other section toclamp said sections together in response to the rotation thereof. i

' )lun er' is forced inwardl a ainst the ten- 1 e V c sion ofsaid'spring.v a

J 5. In a device of the class described, in combination of two sections and assembled for relative sliding movement, said sections having cooperative stops to limittheir extreme sliding movement, one of said sectionshaving a-threaded bore and the other having a threaded plunger adapted to come opposite a bore in the other section when said stops contact whereby said plunger-may, upon rotation, threadingly-enter said bore, positively to lock said sections from movement, and-yielding means normally urging the plunger out of the bore.

6. In a device of the class described, the combination of two sections assembled for relative sliding movement to aposition of extreme extension, aslidable plunger on one of said sections and a hollow nut on the other section, said nut and plunger being adapted to come into registration when said stops contact, a spring normally pressing the plunger away from the nut, sa id plunger having a threaded portion adapteduto engage the thread of the nut when the plunger is pressed against the tension ofthe springand is'turnedangularly. i

7. In a device of the class described, a first section and a second section'slidable relatively thereto, one of said sections having a clip, a clamping means spaced from said clip, and a second clamping means interposed between the clip and the first mentioned clamping means, said second clampmg means-including a plungerwith its ends passing through a bore in one of the-sections and adapted to be screwed into a threaded bore of one of the other sections, the'outer extremity ofthe plunger having a turning member and the inner end having a reduced portion ofsmaller diameter than the threaded bore, and a coil springencircling the plunger for normally projecting said plunger so vas to disengage thereduced end from the threaded bore. 7

8. In an extension leveling rod, the com bination of a lower section and an upper section, means for maintaining said sections in slidable relation, said means including a clamping device having a; clampingmember rotatable Within one ofsaid sections, said rotatable member having means adapted to interlock with co-operating means formed in the other section to press. the-adjacent faces of said sections firmly together in response to rotation impartedto'said clamping n1em-' ber, and'means normally urging said'rotata ble m'ember away from locking engagement with said second section. a s 9.'In an extension leveling rod, the com binatio'nlof a lowersection and an upper section, means for holding said sections together including a rotatable and longitudinally shiftable clamping member extending through one of'said sections, and a threaded portion on the other member,v the inner ex tremity of" said rotatable member being formed: with threads 'to threadingly engage the threaded portion of the'other section in response to the rotation of said member and thereby clamp the sections together, and re silientmeans housed within one of said'sections for automatically controlling the longitudinal shifting of said clamping member.

10. In'an extension leveling rod the combination of two sections assembled for relative: sliding movement, said sections having cooperating stops for limiting the sliding movement thereof at a predetermined point,

one of said sections havingathreadedbore and the other having a plunger positioned to register with the bore invthe other section when the co-operating stops act to limit the relative sliding movementof the parts, said plunger'having athreaded end capable, upon rotation, to threadingly engage the bore to clamp the sections together.

In witness whereof, I have hereunto subscribediny name. s V ADQLPH LANGSNER. 

